-LRB- CNN -RRB- -- Every year the holidays bring cold weather , family gatherings , gift-giving , and of course , the perennial debate over the Constitution and Christmas . Recently , a Long Island school district drew criticism following a performance that removed the holier lyrics from the traditional Christmas song `` Silent Night . ''

Some parents objected when the fifth-grade choir at the school in Kings Park , New York , left out phrases such as `` Christ the Savior '' .

The school superintendent said the principal and choir director removed the references to avoid `` offense to people of other faith , '' according to Newsday .

But regardless of the reason , would it be legal for a school choir to perform `` Silent Night '' in its traditional form ?

To enter the fray we have to understand some of the basics about the often-uncertain relationship between the First Amendment and public schools .

First , let 's dispel the myths : The First Amendment does not ban all mention of any religion in public schools . As the Supreme Court has noted , `` total separation -LRB- between church and state -RRB- is not possible in an absolute sense . ''

After all , when our kids study world history , they are often studying religion . Wars , civilizations , exploration , and human culture have always been motivated in part by some form of dogma .

To filter religion out of history leaves something that can not , in good faith , still be called history . And while some Christmas music consists of light-hearted fare , other pieces are authored by Handel or Bach , and have undeniable value in a musical curriculum . Religion has always been a part of our civilization ; the Constitution and our courts recognize this .

Instead , the Establishment Clause only prohibits the `` advancement '' or the `` inhibition '' of religion by the state . Of course , that 's a distinction that 's much easier to describe than it is to identify in real life . When does a school cross the line into advancing or inhibiting religion ?

In 1971 the United States Supreme Court decided Lemon v. Kurtzman and formulated the `` Lemon Test , '' which is a three-pronged evaluation of the constitutionality of legislation concerning religion . A court will consider the following :

1 . The government 's action must have a secular -LRB- non-religious -RRB- purpose .

2 . The government 's action can not have the principal or primary effect of -LRB- a -RRB- advancing religion , or -LRB- b -RRB- inhibiting religion . It would be impossible to develop a public school curriculum that did not in some way affect the religious or nonreligious sensibilities of some of the students or their parents . Therefore , the test is not `` any effect . '' Rather , the courts will look to the `` principal or primary '' effect .

3 . The government 's action can not `` excessively entangle '' itself with religion -- that is , it can not intrude into , participate in , or supervise religious affairs .

So how does this apply to singing Christmas carols in school ? Fortunately , the courts have squarely dealt with that issue , in the context of ... you guessed it ... `` Silent Night . ''

In perhaps the first case to deal specifically with Christmas music , an atheist father challenged the Sioux Falls , South Dakota , school board 's use of `` Silent Night '' -LRB- and other songs -RRB- in the school 's Christmas program . The Eighth Circuit Court of Appeals -- one of the last stops before the Supreme Court -- applied the Lemon test in Florey v. Sioux Falls School District , and held that both the study and performance of religious songs , including Christmas carols , are constitutional if their purpose is the `` advancement of the students ' knowledge of society 's cultural and religious heritage , as well as the provision of an opportunity for students to perform a full range of music , poetry and drama that is likely to be of interest to the students and their audience . ''

The court also reiterated that :

`` It is unquestioned that public school students may be taught about the customs and cultural heritage of the United States and other countries . '' And that schools may `` allow the presentation of material that , although of religious origin , has taken on an independent meaning . ''

After Florey , it appears that the Establishment Clause does not prevent the singing of Christmas carols with religious origins by public school choirs , though the line seems very thin . For example , if instead of singing `` Silent Night , '' the kids were made to take a quiz testing them on the religious facts undergirding the song :

Q : In the song Silent Night , who is the `` Saviour '' ?

A : Jesus Christ !

Then the school likely crosses into administration of religious training , which is the domain of family and church , not schools . If nothing else though , it certainly appears that `` Silent Night , '' though much more religious than `` Jingle Bells , '' or `` White Christmas , '' is a street-legal public school choir song .

So it appears that schools may include even religious Christmas carols in their curriculum without violating the Constitution . But , can a school go the other direction , and prohibit all Christmas carols from the curriculum ?

At least one federal court has held that they can . In Stratechuk v. Board of Educ. , South Orange-Maplewood School Dist. , the Third Circuit Court of Appeals held that a school district 's policy to bar performance of religious holiday music at seasonal shows , while allowing it to be taught in class , had a legitimate secular purpose of avoiding potential Establishment Clause problems , and was not `` hostile '' to religion .

So schools appear to have broad discretion to include or prohibit Christmas carols , as long as they do n't run afoul of the Lemon test .

Navigating the constitutional perils of religion in school is not easy -- indeed , every year the holiday season brings with it an Establishment Clause debate . The courts and schools will continue to struggle with defining permissible non-secular content . At least there are some less contentious holiday traditions that we can always count on : egg nog , gift returns , and bad decisions at office parties . Happy holidays indeed .

The opinions expressed in this commentary are solely those of Danny Cevallos .

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Danny Cevallos : A New York school district edited lyrics of `` Silent Night ''

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He says courts have delved into issue of singing Christmas Carols in schools

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First Amendment does n't bar all religion from schools , but courts have set guidelines , he says

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Cevallos : `` Silent Night '' is fine for a school choir in most cases